Self-healing gel to repair and connect electronic circuits

After being sliced in half, the gel reassembled and self-repaired(Credit: The University of Texas at Austin)

Researchers at The University of Texas at Austin may have found a solution to one of the key problems holding back flexible, bendable electronics and soft robotics from mass production. Electronic circuits tend to crack and break when repeatedly subjected to bending or flexing, but a new self-healing gel may automatically repair these flaws as they develop.

The gel works without any external stimuli and is meant to be glued or pasted to circuit junction points, because this is where most breakages occur. When damage occurs from excessive bending or normal wear and tear, the gel reassembles itself and reconnects or repairs the circuit.

It is made from combining a conductive polymer hydrogel with a self-assembling metal-ligand gel, which together are stronger and more elastic than the hydrogel on its own. This second component gets its self-assembly – and hence self-healing – capacity from a cubic framework containing soluble molecules called terpyridine, which are held together (structurally speaking) by zinc atoms.

The researcher who created the new gel, Guihua Yu, believes that it has potential applications in batteries and biosensors as well as the more obvious use in electronic circuits. His research team found that by controlling the synthesis of the gel using something called a rational dopant counterion (in this case, a kind of disc-shaped liquid crystal molecule that makes the gel self-assemble into nanostructures), they could achieve about 10 times the conductivity of polymer hydrogels used in conventional rechargeable batteries.

The researchers are also looking at potential applications in medical technology, artificial skin, and soft robotics.